This invention relates generally to pressure transmitters adapted to convert fluid pressure into a corresponding pneumatic or electrical signal, and more particularly to a transmitter that includes a pressure sensor in which the fluid to be metered is applied to a sealing diaphragm on which a force beam is mounted to deflect the beam.
In many industrial process control systems, there is a need to measure a variable fluid pressure and to convert the measurement into a signal for transmission to a remote station for operating indicator or control equipment. In one known form of pressure transmitter for this purpose, a sealing diaphragm is fixed about a high pressure opening and a force beam is mounted thereon. Flexures are provided for absorbing axial thrust of the diaphragm, these flexures being offset from the longitudinal axis of the beam so that the beam is angularly responsive to diaphragm expansion.
In a pressure sensor it is important to be able to vary the operating range of the instrument without altering its static balance. Known arrangements are incapable of making this adjustment, and the range of these instruments is limited by the characteristics of the diaphragm and of the flexures associated with the beam.